(a) Field of the Invention
The present invention relates to a liquid crystal display
(b) Description of Related Art
A typical liquid crystal display (“LCD”) includes two panels and, between them, a liquid crystal layer with dielectric anisotropic characteristics. The LCD displays a desired image by adjusting the strength of the electric field applied to the liquid crystal layer to control the transmittance of light passing through the panels. The LCD is representative of flat panel displays (“FPDs”). LCDs using thin film transistors (“TFTs”) as switching elements are widely used.
The LCD is classified according to its light source, such as: a transmissive LCD which displays images using a backlight unit disposed at the back of the LC panel unit; a reflective LCD which displays images using ambient light; and a transflective LCD in which the transmissive and the reflective LCD characteristics are combined. The transflective LCD displays images under a transmissive mode, using an embedded light source where there is no ambient light (e.g., indoors), and under a reflective mode, by reflecting the ambient light when high illumination is available (e.g., outdoors).
Additionally, a so-called dual LCD, which is provided with two panel units (i.e., a main panel unit and a subsidiary panel unit), has been vigorously developed.
The main panel unit is provided on the inner side and the subsidiary panel unit is provided on the outer side; separate backlight units provide light for each panel unit.
Recently, a scheme in which a single backlight unit provides light for both panel units has been developed. The light from a single backlight unit is divided into two with a beam splitter for the panel units. This LCD has the advantages of being light weight and having a slim display, due to having only one backlight unit. However, dividing the light into two using the beam splitter reduces the amount of the light provided to each panel unit, thereby reducing the luminance of each panel unit.